1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to an ink for a black matrix and a method of manufacturing a substrate using the same.
2. Discussion of the Related Art
Until recently, display devices have typically used cathode-ray tubes (CRTs). Presently, many efforts and studies are being made to develop various types of flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays, and electro-luminescence displays (ELDs), as a substitute for CRTs. Of these flat panel displays, LCD devices have many advantages, such as high resolution, light weight, thin profile, compact size, and low voltage power supply requirements.
In general, an LCD device includes two substrates that are spaced apart and face each other with a liquid crystal material interposed between the two substrates. The two substrates include electrodes that face each other such that a voltage applied between the electrodes induces an electric field across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device. Thus, the LCD device displays images by varying the intensity of the induced electric field.
FIG. 1 is a perspective view illustrating an LCD device according to the related art.
Referring to FIG. 1, the LCD device includes an array substrate 10, a color filter substrate 20 and a liquid crystal layer 30 between the array substrate 10 and the color filter substrate 20.
The array substrate 10 includes gate and data lines 14 and 16 crossing each other on a first substrate 12 to define a pixel region P. A thin film transistor Tr is formed at a crossing portion of the gate and data lines 14 and 16. A pixel electrode 18 in the pixel region P is connected to the thin film transistor Tr.
The color filter substrate 20 includes a black matrix 25 on a second substrate 22 and corresponding to the gate and data lines 14 and 16 and the thin film transistor Tr. A color filter layer 26 corresponds to the pixel region P. The color filter layer 26 includes red (R), green (G) and blue (B) color filter patterns 26a, 26b and 26c corresponding to the respective pixel regions P. A common electrode 28 is formed on the black matrix 25 and the color filter layer 26.
Although not shown in the drawings, a sealant is formed along peripheral portions of the array substrate 10 and the color filter substrate 20 to attach the array substrate 10 and the color filter substrate 20. Alignment layers to align liquid crystal molecules of the liquid crystal layer 30 are formed at the array substrate 10 and the color filter substrates, respectively. Polarizing plates are formed on outer surfaces of the array substrate 10 and the color filter substrate 20, respectively. A backlight unit is below the array substrate 10 to supply light.
When a gate signal is supplied to the gate line 14, the thin film transistor Tr is turned on and a data signal is supplied through the data line 16 to the pixel electrode 18. Accordingly, an electric field is induced between the pixel electrode 16 and the common electrode 28, and images are displayed through the LCD device.
The LCD device is manufactured through a plurality of mask processes to form the thin film transistor Tr, the gate and data lines 14 and 16 and the like at the array substrate 10, and the black matrix 25, the color filter patterns 26a to 26c and the like at the color filter substrate 20. Each mask process includes many steps, such as a step of forming a material layer on a substrate, a step of forming a photoresist layer on the material layer, a step of exposing the photoresist layer to light using a photo mask, a step of developing the light-exposed photoresist layer to form a photoresist pattern, a step of etching the material layer using the photoresist pattern as an etching mask, a step of stripping the photoresist pattern, and the like.
Accordingly, when a number of mask processes increases, production costs and time for the LCD device increase.
The related art requires many mask processes. In other words, four or five mask processes are required to manufacture the array substrate, and four mask processes are required to manufacture the color filter substrate. Accordingly, it is needed to reduce a number of mask processes.